S
M
T
W
T
F
S
30
82°
57°
31
80°
55°
1
78°
57°
2
79°
60°
3
78°
57°
4
78°
53°
5
79°
54°
6
78°
58°
7
77°
52°
8
78°
53°
9
76°
58°
10
77°
53°
11
76°
51°
12
75°
51°
13
76°
55°
14
79°
56°
15
81°
56°
16
82°
55°
17
82°
56°
18
81°
55°
19
80°
50°
20
78°
47°
21
71°
50°
22
72°
52°
23
76°
52°
24
77°
53°
25
78°
50°
26
77°
44°
27
72°
46°
28
69°
45°
29
68°
45°
30
69°
46°
1
70°
43°
2
68°
42°
3
Hist. Avg.
76°
51°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in New Haven
New Haven's September 2026 forecast shows daily high temperatures ranging from 68° to 82°, with overnight lows between 42° and 60°. The average high for September is 76° with an average low of 52°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in New Haven. See also: October | November | December.
